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Polystyrene models. III. modeling backbone/side‐group interactions by an ab initio study of 2,4‐diphenylpentane
Author(s) -
Lagowski J. B.,
Vancso G. J.
Publication year - 1993
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.560460205
Subject(s) - ab initio , chemistry , dipole , steric effects , polystyrene , computational chemistry , group (periodic table) , molecular orbital , side chain , tacticity , molecular physics , crystallography , stereochemistry , molecule , polymer , organic chemistry , polymerization
The Structure and the energy of the stable conformations of the two possible stereochemical configurations of 2,4‐diphenylpentane are obtained using the ab initio molecular orbital theory. The objective was to mimic the possible structures and determine the corresponding energies of the dyads of syndiotactic and isotactic polystyrene and, consequently, to study the interactions between the phenyl groups. The results of complete geometry optimization showed significant changes in geometrical parameters compared with those expected from the ideal hydrocarbon structure. The steric strain is most pronounced in some of the gauche conformations where large (approximately 40°) distortions of the backbone torsional angles and/or simultaneous phenyl group rotations in the range of 30°–40° away from its global minimum position may occur. In addition to the discussion of the geometrical parameters, the corresponding dipole moments are also calculated and differences related to the various structures and discussed. © 1993 John Wiley & Sons. Inc.